My 2 story home has 2 A/C units, one for each floor with a programmable thermostat each, and uses a single boiler with radiators for heat with it's own mercury thermostat downstairs. I have added electric heat into the downstairs air handler and use the existing programmable thermostat, but the upstairs unit is 120v and it is not an economic option to upgrade it. I have closed all the radiator valves downstairs and manually turn on the heat thermostat when I want additional heat upstairs. I'm looking for and have searched the web for wireless thermostats, but mostly find remote thermostats where the base unit replaces the existing thermostat and the controls are the remote. I'm actually looking to replace the upstairs thermostat with one that I can wire to the existing A/C thermostat wires and which has a remote receiver with the relay to operate the heat. Any info on manufacturers and model numbers would be great.

Thanks, Mike

The remote thermostat here can be made to do what you want I believe but you might have to modify to add the relay off a trigger circuit you can make with a extra 24 volt transformer. I do not do system design work here since I have limited time but if you are slick and know a bit about electric you will figure it out.

Venstar Inc. - Thermostats (http://www.venstar.com/Thermostats/)

The remote thermostat here can be made to do what you want I believe but you might have to modify to add the relay off a trigger circuit you can make with a extra 24 volt transformer. I do not do system design work here since I have limited time but if you are slick and know a bit about electric you will figure it out.

Venstar Inc. - Thermostats (http://www.venstar.com/Thermostats/)

Thanks for the answer, I'll look into it.